The invention relates to container securement devices, and more particularly, to improvements in cargo container securement devices of the type that provide automatic securement and release of a cargo container. The device is mountable on a deck or frame of a vehicle or similar surface as desired so that the device can be adapted to different load conditions including a different mix of containers of different length and the like.
This latch device can be used to hold a cargo container onto a vehicle deck such as a railroad car deck. The device can be adapted to hold two cargo containers together such as in the case of double stacking containers. Four latch devices are used to fasten the four corner castings or fittings of a cargo container to a vehicle deck or similar surface. The container's four bottom corner fittings are brought into contact with the top end of the latch device, thereby sliding over the top of the housing and engaging the protruding latch. A cargo container can be removed when the bottom lip of the corner fitting or casting contacts the concave underside of the upper portion of the latch and overcomes the latch's resistance while the container is being pulled off the housing.
A latch device that may be used wherever the present device can be used is illustrated in U.S. Pat. No. 5,570,981. U.S. Pat. No. 5,570,981 is incorporated herein by reference. The present latch device has fewer parts than what is illustrated in U.S. Pat. No. 5,570,981. The present latch device only has one internal resilient spring, whereas the device in U.S. Pat. No. 5,570,981 has two internal resilient springs. One spring of U.S. Pat. No. 5,570,981 may use a material whose stiffness varies and changes with temperature more than a metal type material. Spring stiffness is directly related to the device's engaging and releasing forces of the cargo container. With a single spring made of metal, the spring stiffness rate does not vary as greatly as with a second material of a second spring. The elimination of the second spring permits the engaging and releasing of cargo containers with the desired force over a greater temperature range.
Also, the sheer block of the housing is larger in the present invention allowing room for a larger latch. A larger latch can be stronger and may have an increased service life. The larger latch due to the taller housing can handle larger loads.
The larger latch in combination with the use of only one spring allows greater ability to adapt the latch of the present invention. The shape of the contact and pivot surfaces of the latch's leg may be tailored to create various embodiments with a greater range of container engagement and release features.